What is a Botox Injection Anyway?
The cosmetic form of botulinum toxin, often referred to by its product name Botox, is a popular non-surgical injection that temporarily reduces or eliminates frown Cornelius Juvederm lines, forehead creases, crows feet near the eyes and thick bands in the neck. The toxin blocks the nerve impulses, temporarily paralyzing the muscles that cause wrinkles while giving the skin a smoother, more refreshed appearance. Studies have also suggested that Botox is effective in relieving migraine headaches, excessive sweating and muscle spasms in the neck and eyes. Botulinum neurotoxin is produced by the gram-negative anaerobic bacterium Clostridium botulinum.
Eight serologically distinct botulinum neurotoxins exist, designated as A, B, C1, C2, D, E, F, and G. Seven are associated with paralysis. Types A, B, E and, rarely, F and G are associated with human botulism.
The dose of botulinum toxin is expressed in mouse units. One unit is equal to the amount that will kill 50% of a group of 18- to 22-g Swiss Webster mice when injected intraperitoneally. The human lethal dose (LD) for BOTOX (botulinum type A purified neurotoxin complex) is estimated at approximately 3000 units. BOTOX injections of less than 100 units usually are used for cosmetic purposes and of less than 300-600 units for other purposes, thereby allowing a wide safety margin. Recognizing that doses are not interchangeable among different formulations of botulinum toxin (BOTOX, Dysport, Myobloc) is important; to achieve similar clinical effects, different doses are used.
BOTOX is a sterile lyophilized form of botulinum toxin type A. It is produced from a culture of the Hall strain of C botulinum and purified by a series of acid precipitations to a crystalline complex containing the toxin and other proteins. The FDA approved BOTOX in December 1989 as an orphan drug for the treatment of strabismus, hemifacial spasms, and blepharospasm. BOTOX is distributed in 100-unit vials.
The original batch of neurotoxin prepared by Shantz in November 1979 (designated batch 79-11) constituted the original BOTOX formulation and was used until December 1997. It was replaced by a new neurotoxin complex batch designated BCB 2024. The new bulk batch is 5-6 times more potent on a weight basis. In a 100-unit vial, only 4.8 ng of neurotoxin is needed compared to 25 ng of 79-11. The new BOTOX is comparable in clinical efficacy and safety to the old, and a unit dose of new BOTOX provides an equivalent response to the same unit dose of old BOTOX. Hopefully, the reduced protein load of the new BOTOX leads to reduced immunogenicity and a lower incidence of neutralizing antibody formation.